As Dallas authorities await the extradition of Van Dixson, a suspect in four of the nine recent rapes in South Dallas, questions over the process of the investigating the crimes are mounting.

The suspected serial rapist was first interviewed on Sept. 4, according to police accounts, where he consented to a DNA swab and a search of his residence and car. Police said that DNA connected Dixson to four of the six rapes for which police have physical evidence. Three of the cases no longer have physical evidence, according to police.

In a Twitter conversation Thursday night, Dallas Police Chief David Brown cleared up some questions on the two sexual assault cases that have yet to be confirmed via DNA testing.

In the conversation, Brown said that Dixson “stated that he was involved in one of the DNA match cases” and “thru further discussions with him we believe that is also involved in the DNA analysis that is not yet completed.” Brown went on to add that “we don’t have enough yet to file that case but we will conduct further interviews with him.”

The results of the outstanding cases had been keeping Alan Mason in jail until he was ruled out as a person of interest Thursday by DNA testing. Mason had been previously named by police as a "person of interest" in connection with the rapes, but has since been cleared.

"After discussions with the Crimes Against Persons supervisors and detectives it is believed that Mr. Mason is no longer a person of interest based on the recent suspect interview, further review of the offenses, additional DNA analysis, offense details obtained from the survivors, and suspect M.O. It is the department’s belief that Mr. Mason was not involved in these cases. Although DNA analysis is still pending on one remaining case we don’t believe he is responsible for these crimes due to the above reasons."

Mason has been behind bars on an unrelated probation violation since the early morning hours of Sept. 6.

Police Could Have Held Rape Suspect

The Dallas Police Department had said numerous times that they had no reason to keep Van Dixson in custody when he was first interviewed by police, however documents obtained by NBC 5 on Thursday indicate he was wanted in Plano.

In an unredacted arrest affidavit obtained by NBC 5, the document said, "Dixson had two City of Plano traffic warrants out for his arrest" and that "Since it was unclear if Dixson would be placed under arrest for outstanding warrants... (detective's name) read him his Miranda warning at 19:29."

Plano police confirmed Dixson had two warrants issued on August 16. The two arrest warrants would have been sufficient to hold Dixson in custody.

However, Brown told reporters on Wednesday night that they had no reason to hold Dixson for long enough to get DNA evidence.

"If you don’t have something to hold him in jail for four days, you’re just spinning your wheels," Brown said on Wednesday.

Brown said four days were needed because that's how long it would take to expedite DNA results from one of the victims.

When asked to comment, Chief Brown sent this message to NBC 5's Ray Villeda late Thursday afternoon:

"He would have been in an out of jail the same day not long enough for DNA analysis to come in...it was a trade off. Since we didn't have enough to get a warrant to retrieve his DNA, playing nice to get it voluntarily ended up being the right call. Had he not voluntarily given us DNA we would not have broke the case."

Dixson was ultimately released after his interview and then fled to Louisiana, where he was later arrested after being formally named a suspect in four sexual assaults.

NBC 5 reporters Ray Villeda and Eric King contributed to earlier versions of this report.